Unpredictable weather can cause variations in the size, health and maturity of crops from

year to year.  Large swaths of crops could be destroyed if severe rot strikes forcing vintners

to pick the grapes too soon.  Rot, also known as botrytis bunch rot, is caused by the fungus

Botrytis cinerea.  Botrytis concentrates the flavors and sugars of certain white grapes, which

can be used to produce desert wines when conditions are right.  Vineyards being susceptible

to botrytis depends on a number of factors, weather, grape variety, ripeness levels and the

type of viticulture used.  Botrytis happens most often during harvest time because the grape

skins at that time are thin and loaded with sugar, which is a preferred food of botrytis.  The

fungus naturally resides in vineyards, during winter, it lives on unpicked grapes, dead leaves,

and other decaying plant matter.  When it rains it can dislodge the spores onto grapes, which

can breech the skin and rot the grape.  Botrytis requires freestanding water to grow and

generate spores.  The grapes that are most susceptible are Chardonnay and Pinot Noir due to

their thin skins, Cabernet Sauvignon and Syrah are ticker skin grapes and are relatively rot

resistant.